Suggested fix for Issue #206

Using the following function names results in Migration Issue warning
from Flash Professional:
onKeyUp, onKeyPress, onKeyDown, onMouseDown, onMouseUp, onMouseMove
See Issue #206 https://github.com/AdamAtomic/flixel/issues/206

Replaced all occurances of those names with:
handleKeyUp, handleKeyPress, etc.
(I hope I got them all!)